Capacitors, particularly interdigitated capacitors, are well known in the art of electrical components. Capacitors typically comprise parallel plates, which act as charge collectors and sources, with a dielectric there between. The function of capacitors is well known and further discussion is not warranted herein.
The capacitors are elements that are added to the circuitry with primarily a singular function. The primary function being a source of energy for the circuit to function. In this application, it is counted on only as a reserve of energy hung on to the circuit traces, and in itself does not contribute to the circuit charge or discharge path. In many cases, traces have to be extended from the direct path of the power delivery to connect to the capacitor.
Capacitors are typically secured to a substrate as a component of an integrated circuit. A particularly relevant integrated circuit comprises a microprocessor (IC) mounted to a printed circuit board (as the IC carrier) with large value ceramic capacitors mounted on the opposite side of the printed circuit board in a sandwich type arrangement. This arrangement, while long utilized in the art, is now a limiting factor in the further ongoing miniaturization and speed increase of modem day circuitry. This arrangement is now limiting in two instances. One limitation is the propensity for larger ceramic capacitors to form cracks, and therefore fail, when subjected to flex stresses. Larger capacitors are required because of the higher capacitances required for this application. A second limitation is the necessity to dissipate heat from the circuit as increased functionality and speed increases heat in the silicon.
Stress cracking that is exacerbated with larger capacitors is well known: as the size of a capacitor increases the separation between terminations increases as does the susceptibility to cracking. Any flex in the substrate is therefore amplified in the larger separation relative to a small capacitor with close termination leads.
Heat is typically dissipated by thermal conduction from a component, such as a microprocessor, to a high surface area heat sink. In conventional integrated circuits a microprocessor and heat sink are on the opposite face of the printed circuit board from the capacitor. Heat dissipation is therefore only available on one side of the printed circuit board. Incorporating an additional heat sink path is not typically available because of circuit design limitations. Heat removal within the capacitor typically requires dissipation through the electrical connection to the microprocessor and then to the heat sink.
The present invention provides a novel capacitor, and integrated circuit arrangement, which decreases the propensity for stress fractures from flexing and allows for alternate paths of heat dissipation. The novel capacitor, and integrated circuit, achieves these previously unobtainable goals while still maintaining minimal inductance and resistance, with a potential for reduction of both of these parasitics from previous capabilities.